In many applications, particularly in industrial applications, it is very desireable to burn solid waste materials rather than to transport them off-site for disposal, generally in landfills. This is particularly true for oily solid waste such as oil absorbents, oily rags and used oil filters. Environmental Protection Agency (EPA) regulations place strict disposal requirements and long term liability for the disposal of such items. However, Section 279, subpart C of the EPA regulations allows mixtures of used oil and solid waste (e.g. natural or synthetic sorbent materials, rags and oil filters) to be burned for heat recovery with no permitting requirements. Incineration of these items is therefore highly desirable to the oily waste producer.
Prior art incineration techniques may generally be classified as either fixed installations or portable incinerators. A typical prior art portable incinerator is illustrated in FIG. 1 and indicated generally at 10. The incinerator 10 incorporates a standard 55 gallon open head drum 12 as the primary combustion chamber. Waste material 14 which is to be combusted is placed into the drum 12. The drum 12 is secured to a portable cart 16 by means of a chain 18 which encircles the drum 12 and attaches to either side of the cart 16. The cart 16 is provided with an axle and two wheels 20 which enable the portable incinerator 10 to be easily moved from place to place. The cart 16 is further provided with two feet 39. A drum lid 22 is coupled to the top of the drum 12 by means of a plurality of clamp hooks 24. The lid 22 includes a secondary combustion chamber 26 therein. The cart 16 includes at least one electric blower motor 28 which introduces high velocity air into an airbox 30 attached to the cart 16. This high velocity air is coupled to the secondary combustion chamber 26 by means of an inlet air hose 32.
Once the waste material 14 has been set on fire, activation of the blower motor 28 introduces a high velocity air stream into the secondary combustion chamber and primary combustion chamber in order to create at the upper portion of the incinerator 10 a centrifugal swirl of combusting gases which burn the waste material 14 from the top down. In so doing, the incinerator 10 tends to retain the combustable waste material 14 for a long period of time, thereby effecting the substantially complete burning thereof. Combustion gases are released through an exhaust port 34. The incinerator 10 further includes a spark screen 36 at the exhaust port 34 and an air deflector 38 separating the primary and secondary combustion chambers.
The portable incinerator 10, and others similar to it in the prior art, have the advantage that they are easily portable and may be moved from place to place in order to collect the waste materials 14. However, due to the toxic nature of the combustion gases emitted from the exhaust port 34, the portable incinerator 10 must be moved to an outdoor location prior to ignition. This means that any heat generated by combustion of the waste material 14 is dispersed to the atmosphere. Since the unit is not being utilized for heat recovery (i.e. recycling of the oily waste), it does not qualify for the permitting exemption afforded by the EPA regulations. This exemption is only available when used off and solid waste is burned for heat recovery.
The second prior art incineration technique is the fixed installation incinerator. A typical fixed installation incinerator is illustrated in FIG. 2 and indicated generally at 40. Incinerator 40 includes a combustion chamber 42 which is mounted in a fixed outdoor location. The combustion chamber 42 includes a door 44 which allows access to the interior thereof for placement of waste materials and ignition of these materials. A cold air inlet 46 allows air into the combustion chamber 42 in order to sustain the combustion of the waste materials. A screen 48 is placed over the air inlet opening in order to prevent unwanted foreign materials from entering the combustion chamber 42 and also to prevent escape of the solid waste materials from the combustion chamber 42. Exhaust gases produced by the combustion process escape from the combustion chamber 42 by means of the flue 50. The fixed incinerator 40 has the advantage that some of the heat produced by combustion of the solid waste material may be recovered in order to heat the adjacent building 52. In such a scenario, the combustion chamber 42 includes an internal air space which is not in contact with the combustion gases. Air is withdrawn from this internal air space by means of a blower fan 54 which introduces this air into the interior of the building 52 through the window panel 56. Radiant heat from the combustion of the solid waste material heats the air within the combustion chamber 42, and this air may be applied to the interior of the building 52 in order to recover heat from the combustion process.
The fixed incinerator 40 has the advantage that it allows heat to be recovered from the combusted waste materials. Not only is such heat valuable to the user of the building 52, it also allows the disposal of the waste material to qualify for the permitting exemption afforded by the EPA regulations. Both the heat recovery and the permitting exemptions are significant benefits for the user of the incinerator 40. However, the incinerator 40 has a serious disadvantage. It is necessary for the operator of the incinerator 40 to exit the building 52 every time it is desired that waste materials be discarded. In normal use, several trips will be made to the incinerator 40 with waste materials prior to the materials actually being incinerated within the incinerator 40. Because the heat recovery benefits of the incinerator 40 are most valuable during the coldest weather, it is an extremely undesirable burden for the operator to have to leave the comfort of the building 52 every time waste materials must be discarded.
There is therefore a need in the prior art for a solid waste incinerator which incorporates the advantages of both types of prior art incinerators without exhibiting the disadvantages of either type. Furthermore, there is a need for such an incinerator to qualify for the permitting exemptions afforded by the EPA regulations when oily waste is burned for heat recovery. The present invention is directed toward meeting these needs.